Plant for the production of monochloramine and process thereof

ABSTRACT

A process for the production of monochloramine characterized in that it provides for drawing a portion of water intended for the user and exclusively using the portion for preparing the monochloramine solution. The portion intended for the reaction of formation of monochloramine is subjected to a treatment on osmotic membrane, obtaining osmotized water. Subsequently, there is the reaction of the water with reagents in a reactor. In the reaction step, inside the reactor, the osmotized water enters from a first orifice (C) via a solenoid valve with micrometric regulation (EV 1 ). Inside the same reactor, the base chemical products enter via the respective orifices A and B. The base chemical products enter due to the action of metering pumps (e.g. peristaltic pumps). The system is managed by PLC.

FIELD OF THE INVENTION

The present finding is inserted in the field of systems and methods for the production of monochloramine.

More precisely, concentrated monochloramine with high purity.

According to the invention, monochloramine is obtained by means of controlled reaction process.

Monochloramine, produced in solution in a controlled reaction environment, will be injected into the fluid to be sanitized at the user.

The production in controlled environment, by using osmotized water for preparing the solution inside reactor, ensures a sanitizing product, not affected by the quality of the water that must be sanitized.

BACKGROUND OF THE INVENTION

There exist multiple systems on the market for the production of monochloramine as molecule and consequent use on water circuits, such as water intended for human consumption.

For years, also in Italy, monochloramine has been used in some Sardinian aqueducts.

A recent application that has appeared on the market provides for metering the monochloramine in sanitary circuits as a bactericidal agent.

Specifically, the production occurs by metering the base chemical products (hypochlorite solution+ammonium salts solution) directly over a portion of water drawn from the sanitary circuit itself intended for the user, brought into the machine and then the chemical reagent products are injected over the derived flow; the reaction therefore does not occur in a controlled environment but it is subjected to different variables. The monochloramine is therefore produced with reaction on the same flow of water drawn from the sanitary circuit, without any pretreatment, and is subsequently re-introduced.

Both the system and the claimed process provide for the formation and metering of the molecule of monochloramine in a completely different manner, deeming it suitable to separately produce a concentrated solution of pure monochloramine without any affect from the circuit within which the solution is subsequently intended to be metered.

In this manner, the monochloramine obtained by the present process and with the present system maintains the purity of production regardless of the quality of the water of the circuit intended for the user that must be sanitized, and even more so, the production of the molecule occurs in a controlled environment.

SUMMARY OF THE INVENTION

Object of the present finding is to produce concentrated monochloramine with high purity by means of a controlled reaction process.

In order to obtain this, the system and the machine provide for:

-   -   controlling the pressure of the service water used for the         reaction solution,     -   filtrating over osmotic membranes, obtaining osmotized water of         only the portion intended for the reaction,     -   metering the chemical reagents by means of volumetric metering         pumps, such as peristaltic pumps,     -   controlled introduction of the reagents into a suitable reactor         with said water as reaction solvent,     -   controlling the pH of the reaction environment,     -   metering of the concentration solution thus obtained with         metering pumps in the fluid to be sanitized,     -   analyzing the sanitized fluid with detection of characteristic         parameters which allow automating the metering of the         concentrated solution.

The object of the insertion of an osmotized water production plant, with osmosis membranes only for the reaction water, is to obtain—at the entrance of the reactor (for the subsequent reaction of the reagents A and B indicated hereinbelow)—a dilution solution lacking salts, lacking organic micromolecular substances, extremely similar chemical-physical-organoleptic characteristics regardless of the location where the water serving the plant is drawn.

Regardless of the supply source of the structure in which the machine is installed, the reaction is always ensured and the produced monochloramine will have the same characteristics, preventing the formation of by-products.

Said objects and advantages are all attained by the plant for the production of monochloramine and process thereof, object of the present finding, which is characterized for that provided in the below-reported claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The abovementioned characteristics and others will be more evident from the following description supported by the enclosed drawing tables (FIG. 1; FIG. 2; FIG. 3; FIG. 4), which serve as a merely non-limiting example.

FIGS. 1, 2 and 3: illustrate the functioning scheme of the plant and of the present process,

FIG. 4: illustrates the particular shape of the reaction reactor and placement of the inlets of the reagents and of the osmotized water as well as the housings of the PH probe and of the level control.

DETAILED DESCRIPTION OF THE INVENTION

It is known that in order to obtain monochloramine, a reaction of ammonia and hypochlorite must occur according to the following formula:

NH3(aq)+HOCl—>NH2Cl+H2O

Therefore there are two entering reagents, reagent A and reagent B, which following their reaction produce monochloramine and water.

Said reagents are defined as follows:

with the term REAGENT A, sodium hypochlorite is indicated; in the present invention, the hypochlorite is stabilized at a specific concentration; hereinbelow the REAGENT A will be indicated with the term ACISAN-C.

With the term REAGENT B, ammonium in salt form is indicated, in solution with other substances in order to reach a consistent value of pH and a defined ammonia concentration; hereinbelow, we define the REAGENT B with the term ACISAN-AM.

Ratio Between the Reagents

With regard to the ratio between the reagents, the used formula is the following:

The base reaction for the production of monochloramine:

NH3+HClO=NH2Cl+H2O

wherein:

NH2Cl is monochloramine

NH3 is ammonia

HClO is hypochlorous acid obtained via hydrolysis of the sodium hypochlorite by the following reaction:

NaClO+H2O=HClO+NaOH

In the case of the present invention, the reagent B, i.e. ACISAN AM, contains NH4Cl+NaOH+NH3, hence the overall reaction, in addition to the above base formulation, is also composed of the following reaction:

NH4Cl+NH3+NaOH+2HClO=2NH2Cl+NaCl+3H2O

Description of the Finding

In order to obtain the production of monochloramine, the machine and the process provide for:

-   -   drawing a minimal part of the water, intended for the user, used         for the reaction solution;     -   controlling the pressure of the service water used for the         reaction solution;     -   filtering, over osmotic membranes, the water used for the         reaction solution, obtaining osmotized water. For such purpose,         an osmotized water production plant is inserted with osmosis         membranes, since it is necessary to insert in reaction a         dilution solution lacking: salts, organic micromolecular         substances retained with the osmotic process. All this in order         to obtain extremely similar chemical-physical-organoleptic         characteristics regardless of the supply source of the portion         of water used for the reaction solution;     -   the reaction taking place in a suitable reactor, reference FIG.         2; FIG. 3, as described below, for obtaining pure monochloramine         solution;     -   metering chemical products (ACISAN AM and ACISAN C), contained         in suitable tanks 6 and 7, into the right proportions for         creating a solution with concentration variable between 1 mg/l         and 500 mg/l of monochloramine which is equivalent to 0.73 mg/l         and 365 mg/l of Cl2.

When the monochloramine molecule has been produced, it has a stability that allows being injected into the circuit to be subjected to sanitization, intended for human consumption regardless of whether it is hot or cold water.

The production plant, in a schematic manner, occurs in the following way; the following components are inside the machine:

1) entrance reducer 2 (water entrance line 4) with pressure regulation of the entrance line intended for the reaction solution, manostat 3, with which said pressure values are controlled at: 2-5 bar;

2) an osmotic plant 5; with pump positioned inside the osmosis plant, which takes the water at the pressure reduced by the pressure reducer 2 (see above) and pressurizes it in order to overcome the osmotic pressure (pressure required for making the water pass through the osmotic membranes), giving the residue necessary for feeding the reaction solution;

3) reaction reactor 1 in the detail of FIG. 4; the osmotized water enters into a first orifice, indicated with C, by means of micrometric regulation of the charging solenoid valve, indicated with EV1;

4) the reactor 1 also provides for two further entrances, indicated with A and B, of the components, already previously described, adapted to take part in the reaction.

The process provides for the following steps of production of monochloramine:

-   -   A. the component ACISAN-AM (reagent B) is inserted into the         reactor 1, through an orifice B, simultaneous with the entrance         of the osmotized water. The feeding of the reagent B occurs by         means of a metering pump 8 (e.g. peristaltic) controlled by PLC         until a settable predefined level is reached.     -   B. after the defined time has elapsed or once the preset level         is reached, osmotized water continues to flow to the reactor and         the reagent A, i.e. ACISAN-C enters through a third orifice         indicated with A; the reagent A is introduced by means of pump 9         (e.g. peristaltic) controlled by PLC until a settable predefined         level is reached.     -   C. after the defined time has elapsed or once the preset level         is reached, the previously osmotized water continues to flow,         through C, to the reactor 1, until the final level is reached,         defined by a sensor housed in the space M illustrated in FIG. 4.

The function of the osmotized water, in addition to acting as dilution, due to the internal shape of the reactor allows the indispensable mixing of the base chemical products A and B already described above (ACISAN-C, ACISAN-AM).

In order to avoid the formation of by-products, the monochloramine formation process according to the invention provides that the reaction occurs at regulated pH level, falling within a range defined between PH 8-12. For such purpose, inside the reactor, a probe 11 or pH probe is positioned, housed in the space N of FIG. 4, which verifies that the pH of the solution falls within a range between PH 8-12.

This measurement occurs upon reaching step C. If the read value, at the end of the step C, is outside the range pH 8-12, the system will generate an alarm from the PLC which will block the production and eliminate all that produced outside the aforesaid range.

On the contrary, if the reaction occurred regularly, in compliance with the controls executed by the PLC, and the pH falls within the predefined 8-12 range, then the production of pure monochloramine solution took place and hence the solution descends from the reactor, by means of the solenoid valve EV2, into the storage tank 12, being available for use.

The monochloramine solution that is produced in the reactor 1, obtained via mixing of osmotized water, ACISAN-AM solution, i.e. product B, and ACISAN-C, i.e. product A, (in sequence, first ACISAM AM is metered and then ACISAN C) has a concentration of monochloramine variable between 1 mg/l and 500 mg/l of monochloramine which is equivalent to 0.73 mg/l and 365 mg/l of Cl2.

Once the monochloramine is stored in the storage tank 12, whose level is controlled by a sensor 13, it is metered to the users U1 . . . Un to be sanitized by means of metering pumps 14 which operate according to PID and/or proportional—volumetric logic.

With metering logic of proportional—volumetric type, the metering of the monochloramine occurs by means of metering pump, which injects as a function of the signal coming from a flow rate detector C1 . . . Cn. The signal is proportional to the amount of water that passes by the flow rate detector.

With metering logic of PID type, the metering occurs by means of metering pump which receives a signal from a control unit outside or inside the pump itself. Multiple values reach the control unit, such as: a signal proportional to the concentration of the monochloramine measured on the user U1 . . . Un by means of an analysis system 15 plus a time, insertable by a technician, as a function of a circuit inertia which calculates the time necessary for the metered solution to be diffused in the circuit itself and reach the analysis system. Simultaneously, also the reading of the flow rate detector is inserted.

Substantially, the PID metering depends on three parameters: analysis of the concentration of the sanitizing agent, inertia time of the circuit, flow rate of water to the users. This allows having a regular metering, preventing hyper-concentrations at some points of the circuit. The system also provides for other analyses 15 which can be inserted by the management PLC in regulating the metering of monochloramine in the user U1 . . . Un to be sanitized, such as: Redox potential, pH, free chlorine, total chlorine, free NH3.

Description of the Reactor

The reactor, indicated overall with 1 in FIGS. 1,2,3 and in particular in FIG. 4, is a cylindrical container closed at the base ends.

The lower base reports an outlet mouth for the connection with a storage tank 12 for the produced monochloramine.

The upper base has at least two openings, indicated with A and B in FIG. 4, through which the REACTION A (ACISAN C) and REACTION B (ACISAN-AM) solutions respectively enter. The entrance of the osmotized dilution water is indicated with entrance C.

The entrance C is situated in the lateral cylindrical jacket of the reactor.

The entrance C is not perpendicular to the jacket, i.e. it is not in radial direction.

The entrance C forms an angle of 45°, see reference 10 in FIG. 4, with respect to the tangent of the insertion point with the point H where there is the release of the osmotized water in the reactor, water transported through duct I.

Point H is situated inside the reactor, in the lower zone adjacent to the jacket, but far from the latter.

The product A, as the section of the reactor of FIG. 4 illustrates, is introduced into the reactor, it too in proximity to the point H, but according to an axial direction with respect to the reactor itself; in order to do this, the presence of the duct L is observed, which arrives from the upper base and is extended inside the reactor up to point H.

Therefore, while the entrance of the product A and B is in the same axial direction, of the reactor 1, the entrance of the osmotized water, from the osmotic plant 5, is on a plane parallel to the base of the reactor 1.

Said geometry of the reactor 1 and arrangement of the entrances A, B, C of the products facilitates the reaction thereof and contributes to the mixing of the solutions and the formation of monochloramine according to that provided by the invention.

The product B, as the plan of the reactor of FIG. 4 illustrates, is introduced into the reactor in the orifice B on the top of the reactor itself.

The osmotized water used for the reaction solution of monochloramine is a part of the water intended for the final user; said osmotized water used for the reaction solution of monochloramine is re-introduced into the circuit at the end of the reaction. FIG. 1 indicates an example thereof.

The flow rate of water intended for the user being indicated with E+F, the process requires that a minimal part, F, is filtered by means of osmotic membranes and subsequently introduced into the reaction reactor together with the reagents A and B; then, an equivalent quantity of monochloramine produced by the reactor itself returns into the circuit. 

1. Process for the production of monochloramine characterized in that it provides for: drawing a portion of water intended for a user (U1 . . . Un) and exclusively using said portion for preparing a monochloramine solution; subjecting the portion intended for preparing the monochloramine solution to a treatment on osmotized membrane and obtaining osmotized water, making said osmotized water react with reagents (A, B) in a reactor (1) and wherein the entrance of the reagents (A, B) is in the same axial direction as the reactor (1) while the entrance (C) of the osmotized water is on a plane parallel to the base of the reactor, in non-radial direction, and wherein said reaction provides for, simultaneously with the entrance of the osmotized water in the reactor (1): introduction of the reagent (B) comprising an ammonium solution in salt form, through an orifice (B); once a defined time has elapsed or a preset level has been reached, introduction of the reagent (A), comprising stabilized sodium hypochlorite, through a third orifice (A); in said step, osmotized water continues to flow into in the reactor (1); introduction of osmotized water in the reactor (1) until the final level is reached, measurement of the pH of the pure monochloramine solution produced and verification that said value falls within a range between 8-12; in positive case, discharge of the solution produced in the reactor (1) towards a storage tank (12), rendering the monochloramine produced by the reaction available for use.
 2. Process according to claim 1, characterized in that the introduction of the reagent (A) in the reactor (1) occurs in proximity to a point (H) inside the reactor where the release of the osmotized water into the reactor (1) also occurs.
 3. Process according to claim 1, characterized in that the service water that is osmotized and used for the reaction solution of monochloramine is a part of the service water intended for the final user; said osmotized service water used for the reaction solution of monochloramine is re-introduced into the user circuit at the end of the reaction; the flow rate of water intended for the user indicated with E+F, the process requires that a part, for example F, is filtered by means of osmotic membranes and subsequently introduced into the reaction reactor; then, the equivalent quantity produced by the reactor returns into the circuit.
 4. Process according to claim 1, characterized in that the monochloramine solution which is produced in the reactor (1) has a concentration of monochloramine variable between 1 mg/l and 500 mg/l of monochloramine which is equivalent to 0.73 mg/l and 365 mg/l of Cl2.
 5. Process according to claim 1, characterized in that the reagent B contains NH4Cl+NaOH+NH3.
 6. Process according to claim 1, characterized in that the feeding of the reagents (A, B) occurs by means of a peristaltic pump controlled by PLC until a predefined level is reached.
 7. Process according to claim 1, characterized in that it provides for controlling the pressure of the service water used for the reaction solution.
 8. Plant for the production of monochloramine according to the process of claim 1, characterized in that it comprises at least: a. one osmotic plant (5); with pump positioned inside the osmosis plant, which receives the service water and pressurizes it in order to overcome the osmotic pressure, which is required in order for the water to pass through osmotic membranes, giving the residue required to feed a dilution circuit; b. one reaction reactor (1) in which the osmotized water enters into a first orifice (C) by means of micrometric regulation of a charging solenoid valve (EV1); the reactor (1) also bearing two further orifices (A,B) of the reagents (A, B) set for the reaction; said reactor (1) is a cylindrical container whose lower base bears an outlet mouth for the connection with produced monochloramine storage tank, while the upper base of the reactor (1) has at least two openings through which the reagent (A) and reagent (B) solutions enter which take part in the reaction; the aforesaid orifice (C) being laterally arranged in the lateral cylindrical jacket of the reactor (1) with non-radial direction; a point (H) inside the reactor (1) identifies the point of contact between the introduction of the reagent (A) and of the osmotized water. c. one produced monochloramine storage tank (12), in which the monochloramine solution produced by the reactor (1) is stored and made available for metering to user(s) (U1 . . . Un).
 9. Plant according to claim 8 characterized in that at entrance (4), it comprises a pressure control reducer (2), with which said pressure is controlled to values of 2-5 bar. 